Farm tractors in cultivation consume a big amount of fossil fuels and emit greenhouse gases to the atmosphere. Improving traction performance and power transfer indices of wheeled tractors and field terrain soil with higher traction (pull ability) at optimal travel reduction (TR) can optimize energy utilization. This study compares the traction performance, fuel consumption, and field productivity, of a farm tractor equipped with a new drive wheel “rigid lugged wheel (RLW)” and conventional tire wheel (CTW) in field tillage operations. Tractor with RLW resulted 24.6 kN drawbar pull and 6.6 km.h⁻¹ travel speed at 80% tractive efficiency and 15.6% TR. While with CTW, the drawbar pull and the travel speed were 23.2 kN and 6.0 km h⁻¹ respectively at 68% tractive efficiency and 36.3% TR. The RLW resulted in improved traction performance with similar equipment weight. Tractor with RLW also resulted 220.5% lower TR, 14.8% higher field productivity, and 15.4% lower fuel consumption. RLW can control equipment weight and field traffic intensity with the improved traction performance of wheeled tractors and will make the field operations more energy-efficient and economical. For enhanced field drivability of RLW, further work is required to test for diverse field conditions and differently sized tractors.

High breakage rate is the bottleneck that restricts corn grain mechanical harvesting in double-cropping area in China. The moisture content and compression resistance characteristics of corn grain have important effects on the breakage rate at threshing. In this paper, 5 corn varieties planted in double cropping area were selected and the effects of grain moisture content and compression resistance characteristics on threshed breakage rate were studied. Results showed that both the grains moisture content and the compression resistance characteristics had effects on the threshed breakage rate. The lower the moisture content, the greater the force required for breakage, and the more difficult it was to break. Meanwhile the breakage rate was also related to the displacement during pressing. The smaller the displacement, the lower the breakage rate, but if the displacement was too small, the corn was a silty variety and the breakage rate was still high. When the moisture content was 33%±1%, the threshing verification test showed that the average breakage rate of DH605, LY296 and KN21 was 5.39%, 5.02% and 7.13%, respectively, which was not suitable for grain mechanical harvesting under high moisture content (moisture content higher than 30%). However, the average breakage rate of LK868 and LD6018 was 4.76% and 4.25% respectively, which was suitable for grain mechanical harvesting under high moisture content. This research could provide a reference for corn varieties selection suitable for mechanical kernel harvesting in double cropping area.

Under the conservation tillage model, corn stubble with a complex structure has become the main obstacle for the operation of tillage tools. To better design relevant tillage tools as a reference, this study established a discrete element model of corn stubble. The intrinsic parameters and partial contact parameters of corn single root (CSR) were obtained through physical experiments, and the maximum shear force (F_max) of CSR was tested. F_max was used as the response value, Plackett-Burman test, steepest climbing test, and Box-Behnken test were used to determine the optimal parameters of the discrete element model. The results showed that the coefficient of friction of CSR-CSR, the coefficient of friction of CSR-steel, and the bonded disk radius all had significant effects on F_max (P<0.01). The optimal solution is when they are 0.81, 0.76, and 0.93 mm respectively. Under this condition, the relative error of F_max between the simulation and the fitting equation was 2.85%. In addition, shear validation tests were conducted on CSR with different diameters. Finally, based on the actual size of the corn stubble, a discrete element model of the entire corn stubble was established, which can provide a reference for studying the crushing of corn stubble.

The rotary buryig blade roller (RBBR) is a tillage tool that can both break up soil and bury straw. However, in previous experiments, it was found that the configuration of rotary blades on RBBR will significantly affect its tillage quality. To achieve the optimal structure of RBBR, this study optimized the configuration of rotary blades on RBBR. Additionally, the tillage performance of different RBBRs was evaluated using the Discrete Element Method (DEM). The results showed that after removing loose soil, the optimized RBBR (SR-8-1) achieved a flatter bottom of tilled layer compared to the previous RBBR (SR-6 and SR-9). Specifically, the calculated bottom evenness after tillage decreased by 40.49% and 40.65%, respectively. Furthermore, upon measuring tillage depth, stability coefficient of tillage depth increased by 5.12% and 3.84%. The exported average axial force from the software decreased by 65.72% and 80.39%. The comparison of field test and simulation showed that SR-8-1 was superior to SR-6 in all tillage parameters except power. Therefore, due to the advantages of SR-8-1 in terms of tillage performance, it is better able to meet the tillage needs than other structures.

Aiming at the problem of floating shellfish boxes interfering with kelp harvesting when mechanized kelp harvesting is based on shellfish–kelp mixed culture mode, this paper combines the structural characteristics of the shellfish box itself, designs the kelp harvesting unit test bench and develops a shellfish box separator device. The key factors affecting the box separator’s separation effect were derived through the theoretical analysis. The process of separation of a shellfish box by the box separator is simulated and optimized under the derived boundary conditions. The single-factor test for the separating effect of the box separator was conducted with ADAMS kinematics simulation software. The test showed the optimal utility intervals for the key factors under consideration. Further orthogonal tests were conducted for the three key factors, which were ranked in descending order of importance as box separator separation angle θ, box separator taper angle β and box separator placement depth h. The optimal parameter combination is the box separator separation angle of 31.9°, the box separator taper angle of 30° and the box separator placement depth of 550 mm. Verification experiments have shown that both indicators, the farthest horizontal distance of the shellfish box and the angle of the shellfish box deviating from the box separator, meet the actual production requirements. In summary, the separator can effectively separate the shellfish box from the kelp, and the device is simple in design, quick in operation, and accomplished separation without disturbing shellfish. This study can provide a theoretical basis for the separation technology of kelp and shellfish box under shellfish–kelp mixed culture mode.